中文摘要：

为大幅度提高高级别管线钢的强韧性和可焊接性，把不同Ce含量的高级别管线钢试样退火处理后，用金相显微镜（OM）、扫描电镜（SEM）及能谱分析（EDS）表征分析试样微观组织。结果表明，随Ce质量分数的增加（0～0．0374％），针状铁素体尺寸由9．28μm变为5．58μm；M／A岛形状由块状不均匀分布变成弥散分布的点状或细条状，其平均尺寸由2．22μm减小到1．23μm；且获得了较多细小、弥散分布的含Ce复合夹杂物，可作为晶内铁素体的异质形核核心诱导晶内铁素体形成，并可促使出现感生形核现象，具有形核效果的夹杂物一般在1～3μm之间。

英文摘要：

To significantly increase the toughness and weldability of high grade pipeline steel, high grade pipeline steel samples with different Ce content were annealed and then their micro- structures were characterized by optical microscopy, scanning electron microscopy and energy sepectrometry. The results show that with increasing Ce content, the size of AF decreased from 9.28 to 5.58 μm; M/A island shape shifted from massive uneven distribution to dispersed dots or thin strips, and accordingly size decreased from 2.22 to 1.23 μm; more small and dispersed, Cecontaining inclusions were obtained, which could be used as the heterogeneous nucleation core of intracrystalline ferrite core to induce the formation of intracrystalline ferrite and to promote in- duced nucleation. The inclusions with nucleation effect were generally between 1 to 3 μm in size.